Re: [PATCH 2/2 v2] mtd: ubi: use put_device() if device_register fail

From: Richard Weinberger
Date: Thu Mar 15 2018 - 03:53:49 EST


Am Donnerstag, 15. März 2018, 08:20:31 CET schrieb Arvind Yadav:
> if device_register() returned an error! Always use put_device()
> to give up the reference initialized.

Like DaveM said, there is no need to shout and use "!".

> Signed-off-by: Arvind Yadav <arvind.yadav.cs@xxxxxxxxx>
> ---
> change in v2:
> Fix use-after-free bug. move put_device() after cdev_del().
>
> drivers/mtd/ubi/vmt.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
> index 3fd8d7f..93c6163 100644
> --- a/drivers/mtd/ubi/vmt.c
> +++ b/drivers/mtd/ubi/vmt.c
> @@ -610,6 +610,7 @@ int ubi_add_volume(struct ubi_device *ubi, struct
> ubi_volume *vol)
>
> out_cdev:
> cdev_del(&vol->cdev);
> + put_device(&vol->dev);
> return err;

The more I dig into device code, the more questions I have.
Why is cdev_del() not part of the release function?

Thanks,
//richard